[luke5441]

I think OP only watched the movie. The book is a bit better at showing the main character actually being competent at times. In the movie they (for obvious reasons, but they could have done perhaps once) skip him going down science rabbit holes.

[hgoel]

I think the movie also did a decent enough job of conveying that preparing enough astrophage for just one ship was only barely possible in Earth's environment. It was the entire reason for making it a one-way trip.